Marked sample logs felled at the experiment site at Kershope being transported to the sawmill for processing
Forest Research’s conifer breeding programme has attempted to increase the yield of Sitka spruce (Picea sitchensis) through selective breeding to improve yield of timber product without deterioration in timber properties in comparison to the commonly planted Queen Charlotte Island provenance.
This project aims to evaluate the success of tree breeding through the investigation of the genetic variation in stem straightness, knot size, wood density, microfibril angle and stiffness.
- To quantify the genetic variation of timber properties in improved Sitka spruce progeny
- To determine the most appropriate genotypes for future planting of Sitka spruce in the United Kingdom
- To generate a better understanding of key timber properties affecting wood performance and end-use.
Forestry Commission policy
Timber is one of the key themes of the Scottish Forestry Strategy. This project will contribute to several of the requirements identified in the Strategy, namely:
- To promote predictable and stable timber supplies
- To encourage the use of genetically improved nursery stock
- To encourage the production of high quality timber (where quality is fitness for the intended market) and improvements in yield.
Small clear sample cut from a felled tree being mechanically tested for stiffness and strength
Discs cut from the sample trees from which further samples are taken to measure density and cell wall orientation (microfibril angle)
All of the following properties have been investigated and will in turn be linked to solid timber performance:
- Stiffness: Timber is graded primarily according to wood stiffness. This programme has investigated timber stiffness on a range of scales from small clears to construction sized battens.
- Wood density: Historically the most commonly used measure of timber properties throughout the forest woodchain. Density was measured both gravimetrically and by x-ray transmission.
- Knot size: Larger knots, especially dead knots, generally mean poor timber performance. Knots have been measured by branch size on stems and directly on sawn timber.
- Microfibril angle: The cellulose microfibril orientation of the S2 layer is linked to stiffness. Microfibril angle was measured by x-ray diffraction.
- Stem straightness: Straighter stems produce more logs hence increased yield. Stem straightness was measured on trees and logs.
Protocol for stem straightness assessment in Sitka spruce (PDF-135K)
The project started in September 2004 and will run to December 2007.
All measurements have been completed and data analysis is in progress. Initial results have been presented at seminars and workshops. Publications and research notes will be forthcoming.
Centre for Forest Resources and Management
Tel: +44 (0)1349 862144
Fax: +44 (0)1349 866624
About this project
- Forestry Commission
- Scottish Funding Council
- Scottish Enterprise
- Scottish Forestry Trust
- Biotechnological and Biological Sciences Research Council (BBSRC)
- Centre for Timber Engineering, Napier University
- Department of Chemistry, University of Glasgow
- STFI-Packforsk (Stockholm, Sweden)
- Howie Forest Products Limited (Dalbeattie, Scotland)
- Dr. John Moore - SIRT Programme Leader, Centre for Timber Engineering
- Steve Lee - Forest Research
- Dr. Adrian Hapca – Research Fellow, Centre for Timber Engineering
- Sven-Olof Lundqvist - Project Manager, STFI-Packforsk (Stockholm, Sweden)
- Dr. Alexis Achim - Laval University, Quebec City, Canada
- Dr. Franka Bruchert - Forest Research Institute Baden-Wuerttemberg, Germany